Due to requirements of low weight and compact design portable working tools are usually run by a crankcase scavenged two-stroke engine. However, a crankcase scavenged four-stroke engine is also conceivable. As a result of the crankcase scavenging, oil mixed with the fuel lubricates the engine. This means that the tool can be oriented in different directions while running, such as sideways or upside-down. The tools usually have a carburetor connected to an inlet duct, but also a low pressure injection system can be of interest. Since the tool can be used in a lot of positions there is a risk for fuel drops to accumulate inside the inlet duct and then be tipped into the cylinder when the tool's inclination is changed. This can bring about that the engine stops. The greatest risk for this is at lower engine speed. For this reason, the carburetor is usually placed near the inlet port resulting in a short inlet duct. Considering engine power at operating speed it would however be preferable to use a longer inlet duct. This could however be associated with said difficulties as well as pure space problems. Therefore the carburetor is usually adjacent the cylinder's top section, and provided With some kind of heat protecting baffle. This baffle implies a complication at the same time as temperature problems can still arise for the carburetor. Furthermore, the inlet duct usually turns obliquely downward towards the crankcase. Owing to this the inlet gases can not assist in cooling the critical area around the exhaust port.